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United States Patent | 5,748,639 |
Choi ,   et al. | May 5, 1998 |
A method for testing a plurality of data bits includes the steps of accepting the plurality of data bits at the test circuit, and comparing first and second data bits from the plurality of data bits to determine if the first and second data bits have a common data value. A first comparison signal is generated responsive to the comparison of the first and second data bits. The first comparison signal has a first logic state when the first and second data bits have a common data value and a second logic state when the first and second data bits have different data values. Third and fourth data bits from the plurality of data bits are compared to determine if the third and fourth data bits have a common data value. A second comparison signal is generated responsive to the comparison of the third and fourth data bits wherein the second comparison signal has the first logic state when the third and fourth data bits have a common data value and the second logic state when the third and fourth data bits have different data values.
Inventors: | Choi; Myung-chan (Kyungki-do, KR); Park; Churoo (Kyungki-do, KR) |
Assignee: | Samsung Electronics Co., Ltd. (Suwon, KR) |
Appl. No.: | 637358 |
Filed: | April 24, 1996 |
Apr 24, 1995[KR] | 95-9638 |
Current U.S. Class: | 714/719; 365/201 |
Intern'l Class: | G01R 031/28 |
Field of Search: | 371/21.2,21.1,25.1,27.5,40.4,37.05,22.5 395/183.01,183.03,183.06,183.18 365/201,185.05,185.07,200,189.05,189.07 364/550 |
5311473 | May., 1994 | McClure et al. | 365/201. |
5384784 | Jan., 1995 | Mori et al. | 371/21. |
5400281 | Mar., 1995 | Morigami | 365/201. |
5428575 | Jun., 1995 | Fudeyasu | 365/201. |
5436911 | Jul., 1995 | Mori | 371/21. |
5483493 | Jan., 1996 | Shin | 365/201. |
5506849 | Apr., 1996 | Kato | 371/21. |
5548596 | Aug., 1996 | Tobita | 371/21. |
TABLE 1 ______________________________________ DQ0 DWDQ DQ8 DWDQ DQ16 UPDQ DQ24 UPDQ DQ1 DQ9 DQ17 DQ25 DQ2 UPDQ DQ10 UPDQ DQ18 DWDQ DQ26 DWDQ DQ3 DQ11 DQ19 DQ27 DQ4 DWDQ DQ12 DWDQ DQ20 UPDQ DQ28 UPDQ DQ5 DQ13 DQ21 DQ29 DQ6 UPDQ DQ15 UPD1 DQ22 DWDQ DQ30 DWDQ DQ7 DQ15 DQ23 DQ31 ______________________________________